Galo;
very good job on the app!

But for it to make a perfect barrier every single time, the application would have to calculate the correct barrier-to-screen distance automagically from the other values, and then use that number for the final calculation. Otherwise, you'd get ghosting simply because the calculated "best config" had the wrong barrier distance specified.

i made a formula for that, but it was really rough and ugly so i binned it I probably did it the wrong way round or something. Essentially, it calculated the intersection of two imaginary "eye lines" for two neighboring pixels sharing the same "barrier hole". (it really clears up when you draw it out and draw lines to each eye) It should be possible to devise a simple formula for the actual barrier, too.

oh, and i forgot to say this, but cybereality, you are like a god to me
Just the idea of anyone being able to make a 3d monitor on-the-cheap at home is mindblowing. and to top it off, it's glasses-free! how about that!




edit; well, i feel stupid now, it WAS quite simple!


where d is the actual barrier-to-lcd distance, P is pixel pitch, V is viewing distance and S is eye separation.

here is a google calc based on my 17" screen with 80cm viewing distance.
now if i could only make a similar one for the actual parallax barrier.. hmm



edit 2; I solved the other one too. I'm on fire tonight

W is the entire width of the parallax barrier and R is horizontal resolution, the others are the same as above.
using these equations will provide a perfect barrier, in theory free from any type of ghosting or subpixel leaking!

To print it, you could simply make a photoshop document at your screen's resolution PLUS ONE horizontal pixel, and then create a black/white/black/white/black interlace pattern at 1 pixel intervals(first and last columns should be black if you haven't messed up). When you go to print it you just paste the calculated barrier width as the print size.

here is, again, a google calc based on my 17" monitor(which is, btw, quite precisely 337mm wide!). i should probably look into making a batch file or something so anyone can use it i'm not a programmer though so if someone could write something up(if it's even possible) that would be just great!


anyway, cybereality, do you think it's possible to print it like this? i mean, the printer should be able to scale it to its DPI, right?(assuming it's high enough)

(Lots of edits to try to de-clutter the entire post)

As I said, if you used slanted parallax barriers you wouldn't need to have a perfect match and wouldn't be limited to a high DPI printer. I guess it should also correct the color leaking from subpixels you experienced when not in portrait mode.

Unfortunately there doesn't seem to exist stereo 3D drivers for that, but viewing photos or playing videos should still be possible though. You'd just need to convert them to the correct format or write a script to do it on the fly.

That's what I was afraid of, and I'll bet even if you can get down right the quality is lost when looking at the sides of the screen because the angle would shore more then a pixle?

Grrr If they sell touch screen addons for monitors on ebay it should be no problem to make a polarized screen cover replacement. A 100$ mod to make any screen IZ3D polarized would be great.




Cool, what do you mean slanted and is there a downside to this compared to the other way? Maybe you could talk IZ3D to supporting it? lol

Fredz, that's not going to work for a DIY project. You'd have to design a pixel-perfect "staircase" in order to not cover any subpixels up or leak them to the wrong eye. And, you'd have to design the vertical just as carefully as the horizontal.

on top of that, there are no programs that support it, so you'd have to write your own from the ground up.
if you'd be willing to go that far, writing your own drivers and filters could solve the "staircase problem" and let you use straight lines, IF you could write them to be subpixel-aware. but then you'd have color shifting instead because you messed with the subpixels! bad boy!

Slanted just means that the barrier is placed with an angle in respect to the vertical.

Example with a parallax barrier (rightmost image) :



Example with a lenticular screen :



By slanted I didn't meant "staircased", it's been shown in the paper about Dynallax that the staircased solution is not as good as the slanted one because it does need very precise registration which is not really practicable.

With the slanted technique you don't need an accurate registration, you just need to find the angle that minimizes moiré and then adapt your code accordingly.

The problem with color leaking is already present in vertical barriers with an horizontal RGB subpixels arrangement as Cybereality already said, you can correct this with slanted barriers by doing sub-pixel interlacing. Using a slanted lenticular screen (3DeeSlide) on my iPhone (vertical RGB subpixels in landscape mode), I only saw extremly minor color leakages. My code works at the pixel level, I didn't implement subpixel rendering yet. You can see screenshots and videos that demonstrate this in the corresponding topic.

Yes, that's the downside. But the code is extremely simple to write, it only takes six lines in my image conversion app. The subpixel version should be equally simple and should require 2 or 3 more lines of code at most.

As I said you can correct the color leaking by taking subpixels into account, I wouldn't be surprised that this solution leaks less than a vertical barrier with a screen using an horizontal RGB subpixels arrangement.

I guess someone could ask them to add support for this, but I'm not sure they'd invest time in it if they can't have a return on investement. It doesn't cost anything to ask anyway...

a perfect vertical barrier shouldn't leak at all, and is supported by lots of software so i guess it's just a matter of choosing what you want to spend your time with, printing the barrier or adjusting your software to match your desired angle.

there is no perfect vertical barrier unless the barriers at the side of the screen are a different position, angle and width then the ones in the center. This is much worse then wearing 3D Glasses, I would rather use prism glasses and not drive my self crazy.

since the screen is flat, the pixel pitch is fixed and our eyes are parallel to the screen surface, a perfect vertical barrier does exist and has a fixed line width+line distance across the entire plane. You just have to get your calculations right.

i do realize there's no such thing as a perfect printer, but nonetheless, with enough DPI it's very possible.
a 1200dpi printer has a dot pitch of 0.0212mm. this is more than four times smaller than the SUBpixel pitch of my screen.




on a totally different topic, there should be an infinite number of working 3d hotspots with this tech. The only problem is that you have to keep your eyes in the exact "plane" that you calculated the barrier for.. in other words, you could move your head sideways until you get to another hotspot, but you can't turn your head to look at the screen

EDIT; hmm, i think i had that one wrong.. you really SHOULD turn your head towards the screen for perfect representation.

Hey Ciber!
Very nice work you did there!

I got one question (Sorry for my english I'm from Germany ):
I want to build your no-glasses 3D Technique but there is one Problem, i don't know where to find the Transparency Film you used.
Can anybody give me a tip where i can find this Transparency Film in Germany or how its named here?
It would be so awesome to play Games in 3D without glasses!

Shadow

Not true sorry, this would be great for the center of the screen but the lines on the side of the monitor needs a different width and position. It seems like no matter what there is going to be quality loss. Instead of getting a new monitor, buying a printer and all that I just got an IZ3D monitor on sale at ebay for 200$

@dagbro: Ok, thanks for those equations. I will take a look at the math when I get a chance (crazy week for me here).

@Fredz: Well personally I find the vertical barrier to give acceptable results, and I am not sure how much benefit this slanted design would give. I will accept that it can be better, but how much better? Better enough to just throw out all the software support the current solution has? I mean, right now the parallax barrier works for 3D gaming with the iz3D driver, videos and images with the Stereoscopic Player, online videos with YouTube3D, online photos with Phereo, etc. I'm not really looking to toss that out the window.

@Shadow: You can search for "Transparency Film" on eBay and there should a bunch of sellers that ship internationally. Just make sure to buy the correct one for your printer (ie injet or laser). You have to be careful because not all transparency film is designed to be printed on with printers. Make sure it says either inkjet or laser.

@wuhlei: Well, I know I said the mod costs $5 but it does end up getting more expensive. Technically the final parallax barrier, the ink to print it, and the tape to mount it, do indeed cost under $5. However if you include all the tools and supplies needed (ie a printer, the transparency film used for testing, etc.) and a new monitor just for this purpose, then it can get expensive. I have easily dropped a few hundred dollars or more to complete this project. And the quality is admittedly not up to par with commercial solutions. So if you want the best quality experience, then certainly buy a real 3D monitor like Nvidia 3D Vision or even IZ3D (although there might even be less ghosting with my DIY solution than iz3D). I was thinking maybe people already had decent printers and would only need to buy the transparency film, which is only like $10 for standard 8.5" x 11". And people might also have spare monitors they could use (or maybe they don't mind having to mount and un-mount the barrier every time). In that case it would be pretty cheap.

No, he's right, even if it seems counter-intuitive the spacing will be right as long as your eyes are parallel to the screen surface, even when looking at a giant screen with an infinite width. See this pic :

I don't know either how much benefit this solution would give, but an improved perceived resolution and image quality sound like valuable additions.

I think there should be a reason why most high-end 3D TVs (Philips 3D-LCD and Tridelity ) and virtual reality solutions (Dynallax, successor of CAVE) use this solution instead of the vertical parallax barrier technique.

You won't be able to play 3D games (until someone implements that in a stereo driver), but you can still play movie by using a simple AVISynth script (like I did for the 3DeeSlide). Converting photos or writing a photo viewer should be equally simple.

Since you've got the equipment (printer and LCD monitor) and seem to like experimenting, I thought you'd like to have a try at this technique.

Well yeah, I do like experimenting, so this is something else to try. I will certainly give it a closer look at some point and see if it can work out. I was just pointing out that we lose a whole lot of software support (namely everything) by going down this road. So the results would have to be a great deal better than they currently are in order to justify the cost. But seeing as many other researchers seem to swear by this method, it certainly deserves a closer look.

cybereality;
If you're busy or something, i could calculate it for you.
just tell me your pixel pitch, horizontal resolution, eye width and preferred viewing distance.

you should probably triple-check that the pitch is correct though, because that's probably the most critical factor. multiplying the pixel pitch with your horiz-res would give you the theoretical LCD panel width in mm. then just measure the actual panel width and compare the two. this is because i've noticed some sites supply rounded-down pixel pitches for my monitor(0.264 rounded to 0.26).. we need to use the exact pitch for my equations to work.

well you know what they say; measure twice, print once



edit:
Since the d-value is mostly theoretical anyways, i decided to combine the two formulas, and noticed that viewing distance literally fell out of the equation! This means you can use the same printed barrier for any viewing distance, you increase the distance by moving the barrier a mm or so away from the screen.





here is the new formula:

again, W=total barrier-sheet width, R=horizontal resolution, S=eye separation and P=pixel pitch.
GoogleCalc

You could change the (R+1) in the equation to (R+X) if you want to use X 3d hotspots, otherwise you'd see the first pixel column(s) with both eyes when not in the center one. Note that your photoshop document would also have to be R+X pixels wide for the barrier to work then.

Who's up for converting their TV? A 42" LCD should be easier to convert than a computer screen(printing difficulties aside), since the pixels are so much larger.
and the multiple streams would really work if you had all the seats parallel to the screen(most people do have the couch parallel to the TV, anyways).
Your local graphics/PR shop should be able to print it, if they can provide the needed accuracy.


Plasmas COULD work, too, if the viewing distance and/or pixel pitch is large enough to allow the barrier to be in front of the glass rather than IN it.
haha, maybe i'm getting ahead of myself here, but i see a future where everyone here has got DIY-converted TVs




This shorter one defines B, which is a single barrier width(and the distance between two adjacent barriers, they're the same)

as you can see, it's the same except that it doesn't have the R+1.
not sure there's any use for it though it's just very slightly smaller than the pixel pitch(0.2629 something vs 0.264 on my screen)

Do you think the top LCD on the IZ3D monitor could act as the parallax barrier for the bottom LCD? Maybe even have a webcam to track head movement to shift the barrier on the fly for better view angle. But I bet the pixel/barrier width won't match

I am not sure the iz3D panel can go completely opaque. I believe it is designed to act as a polarizing filter.

i have an idea on resolving the ghosting issues you're having.

Theoretically, there should be NO ghosting at all when you're in the hotspot, so it might be the printer leaving a "fuzzy" edge instead of a straight one. this fits with it printing a higher resolution in one direction than the other. Have you ever studied your barriers through a loupe? Regular binoculars turned the wrong way can often be used as a make-shift loupe on very close ranges if you dont have one

if i'm correct, all you'd need is wider barriers! This would, however, shift the image towards green, since you're effectively blocking off more of the red and blue subpixels. So, to combat that you just lower the intensity of the green channel(either in the monitor settings or in the driver). In effect, you'd sacrifice some brightness for decreased ghosting.

the barrier-to-spacing ratio in the image you print could be 3:2 or 4:3(so there's 4 black pixel columns followed by 3 white and so on) or something. Just make sure you still get the same distance between barriers on the printed sheet! 2:1 would btw theoretically only leave one color visible, but i doubt that's the case in the real world.



you could also try printing it rotated 90 degrees, if you haven't already.
maybe that would fit the DPI better.

wow. this is incredible work. great job!

The suggestions you make have been tried and I believe I even posted some experimental shots some pages back in this thread. Basically I can only increase the duty cycle (ie increase the width of the barriers) with the monitor in portrait orientation. If I do this in landscape mode it causes horrible distortion of the color due to sub-pixel masking. Ghosting is reduced, yes, but the color is completely killed. In that case anaglyph would be preferable. Portrait mode is still a possibility (colors are fine, just brightness is lost) but most games will not run with this format and even if they do you can only use about 30% of the screen when playing them. So that kinda kills the whole point of this project for me personally. So I have come to the conclusion that it will only work with uniform barrier to spacing. And I don't have a loupe, but looking at the barrier with my bare eyes, it looks pretty straight to me. You can also look at those 1080P shots I posted, the lines look straight. I don't think thats the issue. You are right, though, theoretically there should be no ghosting at all. But it seems this is very difficult in practice. The biggest problem is that light bleeds from behind the barrier lines. This is most apparent when viewing my black/white ghosting test image. The black side is nowhere close to black, its more of a redish/blue dark gray color. The white side is tinted yellow/cyan but it is much closer to white perceptually. But what I believe is happening is that light is escaping from off angles (ie not the two angles that will meet your eyes perfectly and match with the pattern). The light can, and does, emanate from potentially infinite different angles within the visible range. Some of those angles are not what we intend, and are what I am referring to as bleeding. This is sort of like ambient light, its not necessarily a straight line to your eye, but you can see it. I had some success by attempting to collimate the light using multiple parallax barriers overlaid onto each other. This forces the light to emanate more perpendicular from the screen (and discards the ones at extreme angles, the ones I believe are bleeding). This did reduce ghosting, but also decreased brightness and significantly dropped the overall picture quality. I felt the current solution in the video was superior to this, even with more ghosting. But maybe there is something else that could be done.

Okay, sorry, haven't read the entire thread

using two overlaid but distanced-apart barriers you should(in theory, as always) see a yellow/cyan color shift towards the left/right side of the screen, is that the loss of PQ you mean? With three identical barriers spaced equally apart, the center of the screen would be unchanged, and both the sides would have a green tint. If you want to overlay barriers, you should only put them print-to-print, since the lines from each eye only cross in one(for each viewing distance) fixed distance from the screen. This only becomes clear once you draw it out on paper.

Using wider barriers would probably be better since the entire image would be uniform(green yes, but uniform ). Maybe you made the barriers TOO wide? just a little bit might work! The green color shift is totally expected in any case, and you should be able to correct it by pulling down green in your graphics control panel.

By doing that though, you'll lose more brightness "per eliminated ghost" compared to using the same wider barriers in portrait mode, but the difference is you could actually use it for something. If you have two prints of your current type barriers(you probably do ), you could make a simple variable-width barrier for testing purpouses by putting them print-to-print and offsetting them veeery slightly. If it's the "fuzzy edge" problem you should see an improvement in ghosting. otherwise, if light is bending away from the straight line or something, apparent ghosting might actually be worse Maybe the printer heats up the plastic behind the dots, making it melt and form a lens?

There could also be light bouncing off the surface of the barriers, and then again on the screen surface before going out through the barrier spaces(ambient light like you said). Do you have a matte or shiny screen surface? i'm thinking it would be worse on a shiny one. (Subpixel ghosting should be worse with wider barriers in this case too)

Anyway, i'm sorry i don't have a printer, otherwise i would have actually tried everything myself before posting all my "theories"..

Hey Cyber. Got an idea but you're the man to try it.
What about making the barriers at least 4 subpixels wide and then make an algorithm (which requires calibration) to display images? Lets say one "barrierelement" after calibration has two blue, one red and one green subpixels. By reducing the intensity of the blue ones in the specific "barrierelement" you should be able to have a somewhat balanced image anyway. I do think some vertical moire would be expected but who knows... The task to make such an app shouldn't really be too difficult either.
The advantage would be wider compability with different displays. Disadvantage is of course the necessary calibration process...

This would certainly work, but it won't be compatible with existing stereo drivers anymore and you'll need to implement the interlacing yourself for images and videos. In this case using a slanted barrier would be a better choice as I said previously, because you'll have less moiré effects and the resolution loss distributed in both horizontal and vertical directions instead of just in the horizontal one.

Yeah. That's of course also a huge miss.

@AntiCatalyst: Yeah, I can try with maybe just doing a slightly wider barrier. The tests I did had a significantly wider width. The parallax barrier I used for the video needed to be placed with the printed side against the screen. So if I use a second barrier, the minimum distance from the first barrier would be the thickness of the transparency film. This might be OK, and even desirable. The second barrier need not be exactly the same pattern. It could be a thinner pattern as to reduce the sub-pixel masking. I have also thought that maybe the light was bouncing off the underside of the barrier and then re-bounding off the screen (I have a glossy screen). This may be the cause of the bleeding. Its also possible that the barrier line itself is not 100% opaque, and the light is simply bleeding through the barrier (which is almost the most obvious answer). In that case, the double barrier might help.

@Likay: That is an interesting idea, but I am not really sure it solves the problems with ghosting. It would simply mask the problem. If there is bleeding, there will still be bleeding if its 3 sub-pixels per barrier or 5 sub-pixels per barrier. It doesn't seem to address the core issue (which is still somewhat of a mystery at this point). It would also break compatibility with existing software, so only really useful for custom applications.

oh, you're right, thinner barriers on the second sheet would solve the color tint while still blocking out stray light. Ideally they would be thinnest on the edges too but that is probably hard to print.

and light could very well be leaking through the barrier as you said, but since the ghosting is purple in colour it seems more likely that the red and blue subpixels aren't getting completely blocked by the barrier.

Unless of course it's the ink itself that's purple-tinted. try printing a black little "blob" and looking through it



You could btw use a double barrier print-to-print if you moved further away from the screen.

It doesn't solve the ghosting in any way but it do give a general compability with different screens. As a bonus the algorithm can be adjusted for different black/transparent widths of the barriers and gives more parameters to experiement with. And yes, of course: softwarewise there's need of a new algorithm. Even if not too complicated, softwaredevs needs to support it.

First thank you cyber for a great free solution.


I was wondering the same thing. How does the polarizing filter work? it's controlled by the second port right? Do you think it's possible to emulate shutter glasses or zalman with the filter?

The front panel layer works as an adjustable retarder. However it's an lcd-panel as well so there's noway it can be used with shutterglasses (to high internal delay of the display). Emulating the zalman would theoretically be possible if the iz3d was just two panels stacked together. However there's also a diffuserlayer between the panels to minimize moireeffects. This extra layer also reduces the possibility to physically emulate the zalman.

So the front panel cannot be used to block one eye per frame?

Should be pretty easy to remove the diffuser, unless it's attached to some thing?

Any one try making parallax barriers for their laptop?

[Yes, if you wear the iz3d glasses. However for shutters it's impossible because of the usual (lcd) high internal lag of the monitor. The front panel can't be used as a parallax barrier either because it's transparent for the eye but is altering the polarization properties of the light. One occasion might be using polarizers in front of each eye, removing the diffuser and running the zalman mode on the back panel and at the same time send the white/black lines to the front... Question is why someone should want to do this.

Don't know. Haven't tried and isn't curious enough to do so.

Would work just as well as Cyberealitys setup if using a good printer.

So I could get a 3D colored image instead of a 3D ghosting effect? Unless the glasses only works on the front panel.

Is the polarized filter on top of the front port lcd or is it the diffuser?

This would make a neat project and I have a cam.

I wonder if you could use the photo exposure paper they use to develop pictures, tape it to your monitor with the template displayed fullscreen to get a hard copy template for your parallax. Then, photocopy that on to a transparent sheet.

industrai; that's a wonderfully old-school idea, but sadly the barriers need to be a tiny bit smaller than the pixels.

cybereality, have you gotten around to trying the wider barriers thing again?

Well this weekend was the first free-time I have had in a while, but I spent the entire day converting my Apple DRMed music collection into standard MP3 format for use on my new Android phone. Really annoying, but I got it all done. Probably just gonna buy my music on Amazon MP3 from now on, the prices are better anyway. Maybe I will take a look at this parallax barrier thing tomorrow...

DRM? oh yeah it's the stuff non-torrenters have to deal with.

Watched the vid, very impressive stuff! I know there are 17 pages and it was already discussed but, I looked at your screenshots and while I could see 3d there were also a lot of lines n stuff- so my question is, if I already own an iz3d should I bother with this? from what I understand I might get less ghosting in exchange for the line artifact thingies.

Just an FYI, the iTunes store does not DRM music any more. Plus, they upgrade the quality to 256kbps. It is actually a pretty good deal.

I still use Amazon when I can, though, out of principle.

@yuriythebest: Well I can't really say if this DIY solution would be any better than iz3D, since I've never seen the iz3D. I know that my Zalman is still better quality than the DIY parallax barrier, but the DIY solution is still decent. I mean, there is a good amount of ghosting. If you look at the 1080P images I posted, you will see that there can be noticeable ghosting in extreme cases (ie the trees in the Resident Evil image). In other cases the ghosting is pretty low (for example in the UT2004 video I posted). And of course you are getting only half the resolution. But the colors are actually a little brighter since you don't have to wear glasses. For me it is mostly just a curiosity thing, and I like to tinker with stuff. If you enjoy tweaking and hacking stuff, then this will be a fun project. If you just want a top quality solution that works, then you need to spend the money and get something like Nvidia 3D Vision. Not sure what to tell you.

@PalmerTech: Yes, I know iTunes does not use DRM anymore. If they did then it would have taken me several days to convert my collection instead of just one day. But the M4A format they use is still not as universal as MP3 (for example, it won't work on Xbox 360), although it does at least work on the Android phones without a problem. But, like you, I would rather support Amazon just on principle.

I created yesterday a parallax Barrier myself following cyberealities guide, my monitor is a LG 22" 1680x1050 (similar to cybereality's monitor) and I used a printer 1200dpi. I coundn't find the dot pitch of my monitor so I used same as cybereality in my calculations. The result looked very good, I was really suprised from the quallity of 3d picture I got. It had some ghosting but it was ok.
I also tried galo's programm but it gives very strange results pattern looks very strange, the line were not in some places thicker and in than in other.
Finally I tried to make a parallax barrier for my android phone (vodafone joy). I used the same I created in photoshop a new image in the size of my phone's screen and I used the same pattern that I used for my monitor to fill the image but I reduce the scale of the pattern to 35% (I played around I bit with the setting before I found out that 35% scale gives me the best results). I get some nice depth with it but on so good as on my monitor. I'm not sure if it possible to get better results on a 2,8" screen.

@fildubek: Awesome man! I'm glad someone was able to replicate my results. Despite what some people might think, I'm not just making this stuff up. I also have plans to try this technique with my Android phone (and maybe an Android tablet at some point). The results aren't going to be as impressive as a monitor due to the limited depth possible on a small screen, but the 3D should still look good. I bet with a properly optimized pattern it could work nice.